(1) Field of the Invention.
The subject of the invention is a multi-resonance power supply with an integral quality factor limiter, designed for DC-DC voltage transformation, characterised by high immunity to overload and rapid load changes.
Present-day DC-DC power converters are required to have high reliability, energy efficiency, compact overall dimensions and a low level of radio frequency interference. Such requirements are collectively met by switch-mode power supplies utilizing the resonance phenomenon. Current resonance allows easy control of output power level, whereas voltage resonance allows minimization of undesired phenomena occurring in transient states during the switching process. With the use of voltage resonance, the switching process can be performed at the time instants when the circuit current and voltage values are at their minimum levels and, consequently, allows minimization of switching losses.
(2) Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98.
A resonance converter designed for operation with an inverter described in the US patent: US 2006/0227577 is known. The converter allows transformation of fluctuating and relatively low voltages obtained from renewable sources of energy to the level required by inverters connected to a power supply network. The converter comprises a parallel resonant circuit to which energy is delivered from a low-voltage source via current switches. The DC/AC conversion process is performed thanks to the employment of the zero-voltage switching method. A high frequency transformer, having its primary winding connected to a parallel resonant circuit, provides electrical isolation and generates high output voltage. The secondary winding of the said transformer is connected to a rectifier with a current, serial resonance circuit. The converter supplies output of 450 V at 25-30% voltage fluctuations.
The converter structure is sensitive to rapid load variations. If the load is suddenly disconnected at the maximum output power, the energy accumulated in the resonant circuit, being as a rule considerably higher than that transferred to the load during a single commutation period, may cause a current flow in the commutation circuit exceeding limit values.